Coupling for electric cables.



v PATBNTED OCT. 16, 1906.

C. F. SGHWENNKER. COUPLING FOR ELECTRIC CABLES.

APPLICATION FILED PERM, 1903.

,IHVENTDR: Charles F. SqhWennK er.

u-WMJ/ \A/ITNESSES UNITED STATES PATENT oEEIoE.

CHARLES F. SCHWENN KER, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ACOUPLING FOR ELEcTmctcABLEs.

Specification of Letters Patent.

Patented Oct. 16, 1906.

Application filed February 14, 1903. Serial No. 143.309.

To all whom it may concern:

Be it known that 1, CHARLES F. S'cHwENN- KER, a citizen of the Unlted States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Couplings for Electric Cables, of which the following is a specification.

The present invention relates to couplings for detachably connecting the ends of electric conductors together, and is especially useful in connecting the endsof the leadcables of'the larger sizes of dynamo-electric machines and transformers to the ends of.

their respective transmission-cables.

The object of the invention is to provide a detachable cable-coupling which will hold the ends of the cable together, so that the mechanical and electrical efficiency of the joint shall equal that of the continuous conductor, and which may also be readily coupled and uncoupled without the use of tools.

The invention will be more readily understood by reference to the accompanying drawings, forming a part of this specification, in which' Figure 1 is an axial section of a coupling and its insulating-sleeve embod 'ng one form of my invention. Fig. 2 is a roken elevation thereof, and Fig. 3 is a perspective view of the sheet-metal lining of the insulatingsleeve.

In the modifications shown in the drawings the ends of the cables are stripped of insulation and metallic conducting sections or thimbles A and A are directly connected thereto by soldering or other suitable means. The thimbles A A are cyl ndrical in shape and of a diameter somewhat greater than that of the insulated cable. The meeting ends of the thimbles are cut in planes oblique to their axes,so that they overlap each other when in position, and their cylindrical surfaces are provided with grooves, which when the thimbles are assembled form a helical recess or path for the reception of a couplingspring 2. The coupling-spring 2 is made in the shape of a helix from thick hard-drawn copper or other good conducting spring-wire, with the radius of the helix somewhat less than the radius of the helical groove formed in the thimbles A A, so that when screwed upon the thimbles it tends to bind more or less tightly in the helical groove and makes good electrical contact therewith throughout joint bridged by the conducting-spring at successive points throughout its length, as indicated in Fig. 2, efficient conduction is insured from thimble to thimble, even though contact between their ends may be defective or entirely wanting. by reason of its seating in the helical groove effectually locks the thimbles against separation by mechanical stresses.

- An insulating-sleeve B is provided for inclosing the coupling and at the same time to serve as a means-for screwing the spring 2 into and out of position, which consists of a cylindrical shell 3, of hard-rubber or fibrous insulation, molded about a sheet-metal cylinder C, in which the spring 2 is contained, and having an axial bore of a diameter somewhat larger than the diameter of the thimbles A A. The metal cylinder C is made from a rolled-up sheet-steel punching having Moreover, the spring ears 4 4 bent in radially from its inner end.

Locking-lugs 5 are formed on the side edges near the outer end of the punching and bent down on opposite sides of the ears 4 4 and act to hold said ears in position and the ends of the punching from sliding relatively to each other. Nibs 6 are formed on the side edges near the inner end of the punching and bent down over the corners of the opposite end to hold the ends from separating.

The ends of the metal cylinder may be rovided with flanged washers or ferrules, i desired.

The helical spring 2 is located within the metal cylinder C and has the ends of its wire ground square to abut against the respective ears 4 and 4.

It is to be noted that in whichever direction the sleeve is rotated the car at the rear or following end will be brought into engagement with the corresponding end of the helical spring 2 and tend to spring the rear convolutions of the spring out of contact with the groove 1 and lessen the friction between the spring and the thimbles A and A, thereby enabling the spring to be unscrewed with com arative facility.

T e sleeve B may have its outer surface knurled to enablethe hand to obtain a better hold thereof, and the length of the sleeve conductor-sections provided with overlapping ends and with grooves in the cylindrical sides which form a helical ath when the sections are assembled, a hehcal spring screwed into said helical path and binding the sections "together, and means to rotate said spring.

2. The combination of cylindrical metallic conductor-sections adapted to be connected to the ends of a wire o'r cable and having overlapping ends and side grooves which form a complete helical path when the sec tions are assembled, and a spring in the form of a'helix whose radius is less than the radius of the helical path screwed into said path and bindingthe sections together.

3. The combination of a cylindrical metallic conductor section or sections provided with a helical groove, a helical spring screwed into said groove, and an insulating-shell surrounding the spring and provided with means for operatively engaging said s ring.

4. The combination of a cyhndrica metallic conductor section or sections, a helical spring screwed into frictional engagement with said section "or sections, and an insulator surrounding said spring and rovided with means for lessening the frictional engageme'nt between the said spring and section or sections and causing the spring to rotate with said insulator. v i

5. The combination of a cylindrical'metallic conductor section or sections provided with a helical groove, a helical s rin screwed into said groove, and an insulating-s ell surrounding said sprin and provided with devices which engaget e rear or following portion of the spring when the shell is rotated in one direction or the other to thereby lessen the friction betweenthespring and conductor secf tions and cause it 'to rotate with the said shell. 6. The combination of a cylindrical metallic conductor section or sections, a helical spring screwed into frictional enga ement with said section or sections, a meta cylin der surrounding said spring and provided with ears for engaging the ends of said spring, and an insulating-shell connected to and surrounding said cylinder and extending beyond the ends thereof. p

a In witness whereof I have hereunto set my hand this 12th day of February, 1903.

CHARLES F. SOHWENNKERQ Witnesses:

[BENJAMIN B; HULL,

HELEN ORFORD. 

